134 Theories and Techniques of Management 



over the top of a seine unless the cork hne is held up above the surface 

 of the water.^^2 Other kinds of fishes attempt to go under the lead line at 

 the bottom so that if the seine becomes snagged or rolls up, they may 

 escape from it. Large seine hauls repeated annually on a specific lake may 

 be used for predicting standing crops of fish in pounds per acre; isolated 

 seine hauls are of little value in this respect."^^ 



Figure 6.1. TVA biologists use gill nets for sampling fish in large deep 

 reservoirs. 



Hoop Nets, Wing Nets, and Trap Nets. A hoop net consists of a cylinder 

 of webbing supported by hoops, open at one end and closed at the other. 

 Inside are two funnels, one just inside the open end of the cylinder and 

 the other midway between the open and closed ends. Hoop nets are set 

 in rivers with the tail upstream and the open end downstream. The cur- 

 rent keeps the hoops separated and the net stretched. Fish move into the 

 net easily through the funnel openings, but have some difficulty in finding 

 their way out again.^^ Usually in swimming around inside of the net after 

 passing through the first funnel, some wander through the second funnel 

 and are then inside the closed end of the cylinder called the pot. Fish are 

 removed from the pot by releasing a drawstring after the net or pot has 

 been lifted into a boat. 



Wing nets are modified hoop nets with short wings of webbing attached 

 to the hoop at the open end of the net. They are used in quiet water where 

 the wings guide fish into the net opening, and are held in a stretched 



